Valve operating mechanism



Jan. 15, 1935. K. R. NISBET 1,988,212.

VALVE OPERATING MECHANISM Filed Nov. 4, i932 Patented Jan. 15, 1935 UNITEDN'STATES FATE FFICE 9 Claims.

This .inventionirelates to new and useful improvements inoperating :mechanism for valves of the tappet type and-is especially designed for use in internal combustion engines, although not necessarily restricted in its use.

The typesof valve actuatingmechanism now in common use for tappet valvesinclude a spring operatively connectedto the stem of-the valve for seating the headof the valve, .a tappet or push rod operatively associated with one end of the valvestem or with anuend of an additional rod or rods operatively connected to the valve stem, and a rotating cam, eccentric, or the like, for actuating the tappetorpush rod. In this type of mechanism, it is essential-that ajgap or clearance be maintained between certain :of the cooperating elements .topermit-expansion due to dissipation of heat through themechanism. In valve mechanismsof the above referred to conventional types, this clearance is usually provided between the adjacent ends of the tappet and the valve stem or associated-rod. To, maintain ,a proper clearance at thispoint the tappetis usually provided with some form'of adjustment'by means of whichthe overall length ofthe tappet may' be varied. This adjustment usuallygconsists of a stud threaded into the end of the tappetgand maintained in adiusted, positionby meansoflock nuts.

.,With the valveoperating mechanism of the above mentioned types, wear-occurs at'at least twodifierentpoints; namely, at the point of contact between thetappetrand the actuating cam or eccentric and thepoint of contact between the tappet and the valve stemor operating rod. The clearance,providedbetween the adjacent ends of the tappet and the'valve stem. or operatingrod, .due to wear or improper adjustment at the above mentioned points, not infrequently varies or increases with the result that a tapping noise is produced every time the tappet andvalve stem ends contact. .It not infrequently} is-a difficult. proposition to locate the valve actuating mechanism causing the disturbing noise in view of the fact that either or both of these contacting ends may have one or more-flat surfaces or regions which are not'truly right angularlyarranged with respect to the axis of the tappet and valve stem. Due to frequent periods ofipartial rotation of the valve stem and tappet, these .flat regions will be moved into and out of positionswhich will cause the above referred to tapping noise to startand stop. at irregular intervals. ,Excessive or insuflicient clearance caused by the above mentioned wear oriaulty adjustment also will result in a decrease in the efliciency of the engine. v,

It is a fundamental: object of this invention to provide a valve'operating mechanism which will allow for necessary expansion due to dissipation of heat, eliminate tappetnoises, reduce we'arfbeing description:

Figure l is a detailview, partly in section and partly in elevation, of a portion of the mechanism shown in Figure 2;but viewed .at .right'angles thereto, a

Figure 2 is a sectional view ofone form. of .wvalve actuating mechanism embodyingthis invention,

Figure 3 is axplan-view of .a blank from which one of the elements disclosed in Figs. 1 and 2m'ay belformed, .2

Figure .4 discloses detail views of the connector element which is madefrom the blank shown in Fig. 3, and i Figure5 is adetail longitudinal sectional view' of a modified form of the invention.

In the drawing, wherein for the purpose of illustration is shown a preferred embodimentof the invention, the numeral 6 designates in its entirety the portion'of an engine block or head which has the inlet and exhaust valves operatively associated therewith. This engine part 6 is formed with a valve seat 7 against which the head Biol the valve engages to control the flow A of fuel or burned gases through-the-passageway 9. The valve .head 8 is provided with a stem. 10

which passes through a valve guidell carried-by the engine portion 6-. The valve stem 10 has associated therewith, in any conventional manner, a spring 12 which functions to urge the valve head 8 toward the seat 7. The lower end of the stem 10 is formed with an annular groove 13 and this grooved extremity of the valve is operatively associated with the tappet'or pushrod 14. The upper end or extremity of this push rodalso is provided with an annular groove which bears the reference character 15. The grooves 13 and 15 are shown with square edges, but maybe beveled, or round as desired. Thepush rod 14 16 which. is positioned in operative relation with is provided at its lower end with an enlargement respect to a cam element 17 carried by the cam shaft 13.

In Fig. 3 there is disclosed a blank 19 which is cut away, or bifurcated at its opposite ends 20 to form the spaced, parallel fingers 21. The inner edge of each of these fingers 21 is provided with an offset portion 22. These offset portions do not extend the full lengths of the fingers but form portions raised with respect to the planes of the fingers. The blank constructed in a manner illustrated in Fig. 3 is intended to be formed of elastic material, such as spring steel, and to be bent into U shape, as illustrated in Fig. 4. Figs. 1 and 2 illustrate the adjacent ends of the valve stem 10 and tappet 14 as having'one of these U shaped spring connector units associated therewith by inserting the fingers 21 into the annular grooves 13 and 15. It will be noted that these fingers straddle the valve stem' and tappet when thus positioned thereby permitting the tappet to rotate on its vertical axis when the design is such that this is essential or necessary. The offset or raised portion 22 formed in the fingers 21 will provide seats to receive the adjacent portions of the valve stem and tappet to prevent unintentional removal of the connector unit from its intended position. Due to the resiliency or elasticity of the connector unit 19 the adjacent, opposed ends of the valve stem 10 and tappet 14 are maintained constantly in contact with each other.

When the valve mechanism shown in Figs. 1 and 2 is associated with an engine, the overall length of the mechanism should be such that a clearance will be provided between'the inactive portion 17a of the cam 17 and the enlargement 16 of the tappet 14 when this inactive'portion 17a of the cam is opposite the said enlargement. This gap or clearance 23 will allow for necessary expansion in the mechanism due to dissipation of heat therethrough.

- Figure 5 discloses a modification of the structureshown in Figs. 1 to 4, inclusive. modification, the valve stem 10a is provided with a transversely extending hole 13:; and the adjacent end of the tappet 14a is provided with a transverse hole 15a. A spring connector unit 19a is positioned with the offset portions 22a of its arms 21a positioned within the holes 13a and 15a. The wire connector element preferably is provided with one or more coils 24 which will function to constantly urge the arms 21a toward each other.

It will be noted from the above description of this valve mechanism that no gapor clearance is' provided between the'adjacent ends of the valve stem 10 and the tappet 14. In view of this fact no wear can occur at this point and it is very apparent that the ends of these members will not be rapidly moved into and out of contact with each other and no tapping noise can possibly be produced. With the necessary gap or clearance provided at the point 23, or between the enlarged end 16 of the tappet and the periphery of the cam 17. There will be noengagement between the cam and tappet while the inactive portion 17a of the cam is opposite the tappet end 16. Engagement of the cam with the tappet will only occur while the active portion of the same is functioning to raise the tappet for actuating the valve. It will be apparent, therefore-that wear at this point in the mechanism materially will be reduced, The cam shafts of in ernal com- In this bustion engines ofconventional design are usu ally located in the crank case of the engine with the tappet projecting through a wall of the case. Theassociated surfaces of the cam 17 and the enlarged end 16 of the tappet 14 therefore will be constantly supplied with a film of oil from the crank case. This oil film will function to mate rially reduce wear at this point in the mecha: nism and will assist in preventing the development of any noise at the time of contact.--f

While my invention has been disclosed in connection with a valve mechanism suitable for an L or T head type of engine, it is to be understood I that the invention may be as readily employed in connection with valve-in-head engine's. When the invention is used in a valve-in-head engine, it may be necessary to use either of two types of spring'connectors at more than one point in the mechanism.

It is to be understood that the forms of this invention herewith shown and described 'are to be taken as preferred examples of the same, and that various changes in theshape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. Engine valve mechanism comprising a valve, a seat for the valve, means for urging the valve towards its seat, a'valve lifting rod, a rotatable actuating element, and means for connecting the valve and its actuating rod to prevent separation of the same whereby the clearance left for ex= pansion will occur between the actuating rod and the rotatable actuating element, said means comprising a substantially U-shaped spring meniher having its arms directly and detachably connected to said valve stem and lifting rod.

2. In combination, a valve having a stern provided with a groove adjacent its end, a valve push rod. coaxial with the stem provided with a groove adjacent its end, a cam for lifting the push rod Q and valve, and means for connecting the adjacent grooved ends of the push rod and valve stem to prevent separation of saidv ends, comprising a substantially U-shaped "spring memberhaving portions engaged in said'grooves; I

3. In combination, a valve havingfa'stem,a valve push rod coaxial with thestem, a cam for lifting the push rod and valve; and a substantially U-shaped spring connector elementhaving its arms directly connected to the valve stem and push rod to prevent separation of the same.

4. In a valve operating mechanism, a connector I for directly connecting and maintainingthe valve stem and pushrod of said valve operating mechanism constantly in contact with each other comprising a substantially U-shaped spring member.

5. In a valve operating mechanism, a connector for maintaining the valve stem andpushrod of said valve" operating =mechanis'm constantly in contact w'i'theach othercomprising a substantially U-shaped spring'member having its arms formed with oppositely offset portions adapted to engage a valve stem and push rodto prevent unintentional removal of 'said spring member. 1 r 1 6. In a valve operating mechanisinj a connector formaintaining the valve stem and push rod of said valve operating mechanism constantly in contact with each other comprising a substantially U-shap'ed spring member having its arms bifurcated.

,7. In a valve operating mechanism, a connector for maintaining the valve stem and push rod of said valve operating mechanism constantly in contact with each other comprising a substantially U-shaped spring member having its arms bifurcated and ofiset portions formed in the inner sides of said furcations.

8. In a valve operating mechanism, a connector for maintaining the valve stem and push rod of said 'valve operating mechanism constantly in contact with each other comprising a substantially U-shaped wire spring having a coil intermediate its ends and an offset portion in each arm.

9. In combination, a valve having a stem, a

valve push rod cooperative with said stem, means I KENNETH R. NISBET. 

